Prep Of Alkene And Alkyne

Question 1

Kolbe’s electrolyte

Answer 1

2(CH2COOK) –> CH2=CH2+2CO2+H2+2KOH

Question 2

Dehydrohalogenation

Answer 2

CH3CH2X + B+ (BASE) —-> >C=C< + B-H + X-

Question 3

Alc KOH & heat

Answer 3

CH3CH3-Br —> CH2=CH2 + KBr + H2O

Question 4

Saytzeff’s rule
(The poor becomes poorer)

Answer 4

Stability of alkene is directly proportional to number of Alpha hydrogen

Question 5

Limitations of syatzeff’s rule

Answer 5

1. Not followed if leaving group F, NR3, SR2
2. Rule of conjugation dominates
3. If bulky base- catalyst

Question 6

Vicinal dihalide gives

Answer 6

Alkene

Question 7

Tetra halogen derivative gives

Answer 7

Alkyne

Question 8

Dehydrating agents (H2SO4, H3PO4, KHSO4)

Answer 8

CH3CH2OH –> CH2=CH2 + H2O

Question 9

Carbocation can undergo rearrangement to form more stable carbocation

Answer 9

More the stability of intermediate, more the rate of reaction